Question
What is water gas? How will you prepare hydrogen from water gas?
Or
How is dihydrogen prepared on a commercial scale?
Solution
Water gas is a mixture of CO and H2 in the ratio of 1 : 1 by volume. It is prepared by passing steam over red-hot coke (carbon at 1270 K).
(i) From water gas, hydrogen is prepared, by Bosch process. Here water gas is mixed with steam and passed over a heated catalyst (Fe2O3 + Cr2O3) at 770 K when carbon monoxide is oxidised to carbon dioxide.
The resulting gaseous mixture (CO2 and H2) is passed into cold water under a pressure of the 20-25 atmosphere. Under this pressure, CO2 goes into the solution while dihydrogen gas is left behind and collected.
(ii) By liquefaction: Water gas is cooled under pressure when CO gets liquefied while dihydrogen gas passes out.
(i) From water gas, hydrogen is prepared, by Bosch process. Here water gas is mixed with steam and passed over a heated catalyst (Fe2O3 + Cr2O3) at 770 K when carbon monoxide is oxidised to carbon dioxide.
The resulting gaseous mixture (CO2 and H2) is passed into cold water under a pressure of the 20-25 atmosphere. Under this pressure, CO2 goes into the solution while dihydrogen gas is left behind and collected.
(ii) By liquefaction: Water gas is cooled under pressure when CO gets liquefied while dihydrogen gas passes out.
